The technical scope of the invention is that of projectiles, in particular large-calibre long-range field artillery projectiles.
An increase in the range of artillery projectiles has long been sought after. Thus, a base-bleed has been installed to the tail end of ballistic trajectory projectiles which is designed to reduce the drag of the base by means of the emission of gases developed by the combustion of a composition such as propellant. The base-bleed only increases the range of the projectiles by around 5 to 10% and generates dispersions, which prejudice firing accuracy.
A further proposition to increase firing accuracy has been made consisting in effecting a correction of the trajectory or by terminal guidance. But as ballistic trajectory projectiles are spin-stabilised, it is very difficult to carry out accurate trajectory correction or terminal guidance. Moreover, only accuracy is improved, the range remaining relatively short.
Patent WO100908 proposes an artillery projectile fitted with a base-bleed having a drive band, piloting ailerons and stabilising fins. This projectile is fin-stabilised over part of its trajectory during which the base-bleed is operational, and then the base-bleed is ejected, which enables the deployment of the stabilising fins, which brake the rotation of the projectile. The projectile is thus on a trajectory stabilised by its fin tailpiece. Thereafter, terminal guidance can be carried out by means of the piloting ailerons.
Such a concept has several drawbacks. Firstly, the passage from a spin-stabilised trajectory to a fin-stabilised trajectory generates numerous constraints. In fact, the fin tailpiece is subjected to strong mechanical stresses during its deployment, which can generate a loss in the stability of the projectile and/or considerable dispersion. Furthermore, as explained previously, the range of such a projectile is relatively short.